Traditionally, sports involving the use of ball-bats, e.g., baseball and softball, use wooden bats made of ash or other hard woods. These wooden bats are expensive, time consuming to manufacture, and once broken cannot be satisfactorily repaired to be put back into effective use. So, over time, a metal, and usually aluminum, ball-bat was introduced into baseball and softball as a substitute for the traditional wooden bat because it was relatively inexpensive to manufacture and had a much longer useful life than a wooden bat. In fact, even when slightly deformed through repeated impacts with a baseball or softball, an aluminum bat can still be used. However, even an aluminum bat is generally thought of as having a finite useful life until the aluminum bat becomes so deformed, for example, even taking on triangular or square shapes of deformation, the aluminum bat must be retired. Once an aluminum becomes deformed to this extent it can simply not be effectively used to swing at and strike a ball to achieve desired results.
Use of aluminum bats reaches from little league softball and baseball, to collegiate use, to professional softball and to use in international amateur sporting events. About the only sporting teams regularly using traditional wooden bats are those playing professional baseball. So, manufacture, sale and use of aluminum bats far outpaces wooden bats.
Most aluminum bats are generally less expensive use than wooden bats there are softball and baseball teams that simply cannot afford to replace deformed aluminum bats as often as needed. Little league baseball and softball teams in economically disadvantaged areas often cannot afford to replace old and worn-out equipment, even equipment as integral to softball and baseball games as the aluminum bat itself. Furthermore, it has become commonplace for high school and even collegiate athletic programs that have become short of funding for their teams to be forced to cut costs by not only keeping old and deformed aluminum bats in softball and baseball rotation, but even cutting funding for entire sports teams.
Of course, old aluminum bats that should have been long since retired from use do not simply represent an economic burden on those little league, high school, and collegiate teams, et al., who cannot afford new bats, but also those deformed aluminum bats are still used by those batters who are waiting for a perfect pitch and are thus placed at a serious competitive disadvantage when facing teams with the funding to provide new equipment to its players. In order to, as nearly as possible, allow equally talented teams compete on equal footing it would be a great advance to enable all teams to perform on the playing field with equally sound equipment.
On the other hand, contemporary aluminum bats and bats made of other non-wood materials can be very expensive and very costly to replace regardless of who the purchaser may be. One example of such a contemporary bat is seen in U.S. Pat. No. 5,676,610 on a bat having a rolled sheet of resilient material inserted into the barrel. This type of bat has a relatively thin metal barrel and, while the resilient insert is intended to spring the barrel back after an impact, is more easily deformed by the impacts caused when, for example, a professional softball player hits a home run.